1. Field of the Invention
The present invention relates to a tube, for passing a fluid therethrough, suitably used for a heat exchanger of a radiator or the like.
2. Description of the Related Art
In a heat exchanger tube disclosed in Japanese Unexamined Patent Publication No. 10-193013, a grooved receiving section of a U-shaped cross-section is formed along one side edge of a sheet-like workpiece, while an inserting section is formed along the other side edge thereof, both of which are abutted and welded together by a brazing to form a tube body for allowing a fluid to pass therethrough.
In this regard, since the grooved section of a U-shaped cross-section is formed by bending a sheet-like workpiece through a roll forming process or others, the grooved section is liable to open after the bending (roll forming) due to spring-back to increase the groove width (a distance between opposed inner walls of the groove).
This makes a gap uneven between the inner wall of the grooved section and the inserting section, resulting in a difficulty in securely fixing the grooved section to the inserting section by brazing as well as in improving the yield of the brazed tube.